Analysis firm IDC has slashed its worldwide PC shipments estimate to a growth of “just” 4.2 percent in 2011, down from a February forecast of 7.1 percent.

The PC market is still seeing an echo effect from the foregone netbook boom, which opened up consumers’ minds to smaller and cheaper devices such as smart phones and tablets, IDC analyst Bob O’Donnell said today in a news release. People also are still feeling the financial effects of the Great Recession.

“Consumers are recognizing the value of owning and using multiple intelligent devices and because they already own PCs, they’re now adding smart phones, media tablets, and eReaders to their device collections,” O’Donnell said. “And this has shifted the technology share of wallet onto other connected devices.”

That echoes what IDC said in April, when it declared that smart phones and tablets – and a general boredom of today’s PC options – are eating away at PC sales. And any effect from cool new PCs is still far off.

“The potential boost to the PC market from thinner designs, longer battery life, instant on, touch, and other improvements will likely not be widely available until 2012, and will have to address price-sensitive buyers in order to drive higher levels of growth,” IDC said today. “In fact, the appeal of these future enhancements could be seen as another motive for consumers to delay the purchase of a new PC until they are available and to focus on other products in the meantime.”

However, there is light at the end of the tunnel. IDC expects worldwide PC shipments to spike back into the double digits next year through 2015, when growth is forecast in the 10 percent to 11 percent range.